The corpus, every claim citable.

Sūrya-Siddhānta iii builds working astronomy from a gnomon: on a leveled surface, a drawn circle and a twelve-digit vertical stick yield the cardinal directions (from the shadow-tip's morning and evening crossings), the observer's latitude (equinoctial noon shadow, iii.17), and time-of-day quantities. Burgess's commentary works the rules for Washington, D.C. and gets its latitude right. The gnomon procedures are the observational ground floor of the siddhānta's parameter system.

Translation of the Surya-Siddhanta · tr. Ebenezer Burgess, 1860